Valve



1944- J. L. GRATZMULLER 2,34

VALVE Filed May 8, 1941 Patented Feb. 29, 1944 VALVE Jean LouisGratzmiiller, Paris, France; vested in the Alien Property CustodianApplication May 8, 1941, Serial No, 392,571 In France March 11, 1940 2Claims.

The present invention relates to seats for valves made of a plasticmaterial or at least including a portionof a plastic material coming incontact with the seat and adapted toreceive, on its free side, theaction of a fiuidpressure.

,The invention is more especially,although not exclusively concernedwith the valve seats to be provided-in devices, such as oleo-pneumaticac- Gumulators of energy, oleo-pneumatic shock-absorbers, etc., whichinclude a part such as a bag the bottom portion of which, acting as avalve, comes to bear against the bottom of a container in which the seatin question is provided.

In devices of this kind, seats for the portion of the bag acting as avalve were constituted merely by the bottom wall of the container (forinstance made of metal) provided with holes of a diameter sufficientlysmall for permitting the stopping thereof by the application thereon ofthe bottom portion of the bag, without the material which forms the bagor the bottom portion thereof being able, atleast theoretically, topenetrate into these holes, which would injure the bag and cause it toburst.

However, in devices of this kind, difiiculties of operation have oftenbeen experienced in view of the fact that the plastic matter of whichthe bag (or at least the bottom portion thereof) is made has a tendency,under the effect of the high pressures existing in this bag, and despiteall the precautions that may be taken for the manufacture of said bag,to penetrate into the holes of the container and to be cut by the edgesof said holes.

The chief object of the present invention is to provide seats for thevalves of the type above referred to which are better adapted to meetthe requirements of practice and in particular which avoid the veryserious drawback just above mentioned.

With this object in view, according to a feature of the presentinvention, seats for valves of the type above referred to areconstituted by holes of a particular shape capable of cooperating in asatisfactory manner with the plastic valve element, this particularshape being that of a frustum of a cone, the inclined wall of which isjoined by curved surfaces without sharp edges to the bottom of thecontainer in which the valve seat is formed. As any sharp edge isavoided in the portion of the container wall adapted to cooperate withthe bag or other plastic valve element, there is no danger of said bagbeing cut.

Thus according to the invention, each hole is given the shape of aconical pit prolonged eventually by a cylindrical hole, the plasticmaterial of which the valve is made penetrating into the conical portionof the hole and settling therein without coming into contact with anyprojection or sharp edge that might injure and finally cut it.

With this arrangement, the holes, instead of having a cross section assmall as possible, have a cross section, in the plane of the bottomsurface of the container, which is relatively great, this cross sectiondecreasing gradually until it reaches a minimum value which then remainsuniform and corresponds to the cylindrical portion above referred to. I

Contrary to What might be supposed, this increase of the area of thecross section at the top part of the hole is favorable to a goodpreservation of the matter of which the valve element is made and alsoto fluid tightness of the valve system.

Another object of the present invention is to provide an elastic orplastic valve well adapted to cooperate with valve seats as abovedescribed.

With this object in view, and according to a second feature of theinvention, the valve element, constituted for instance by the bottomportion of a bag, is made of relatively important thickness, in view ofthe cross section of the holes, so as to form a mass adapted to cram orpack in the frusto-conicalportion of the orifices.

According to still another feature of the invention, the bottom portionof the bag, reinforced in the usual manner by the addition of,

layers of fabric, by calendering, etc., is provided, on its outer face,intended to cooperate with the holes in the container, with a layer ofrelatively soft plastic material, which facilitates the, packing of thebag in the orifices and prevents the resistant portion of said bagbottom from undergoing important deformation in these orifices.

Other features of the present invention will result from the followingdetailed description of a specific embodiment thereof.

A preferred embodiment of the present invention will be hereinafterdescribed, with reference orifice the shape of which has, on the sidecorresponding to the inside of the container, a frusto-conical portionI, joined to the bottom 2 of the container in question by a roundedportion 3. This frusto-conical portion I is prolonged by a cylindricalportion 4, without any sharp ridge or projection of the inner wall ofthe hole. The plastic matter which constitutes the valve element, forinstance the bottom portion of the bag, is shown at 5.

As shown by the drawing, this matter, under the effect of the pressureto which it is subjected, penetrates into the mouth of the hole and iswedged or packed therein. In the top portion of the hole, this matter isunder tension and, moving downwardly, a point is reached where a stateof equilibrium exists owing to the reaction of the wall of the hole(arrows 6) having the same value as the pressure, designated by arrow 1.From this point downwardly, the plastic matter of the bag is merelycompressed and it has no tendency to be injured.

As above explained, I preferably provide, along the under surface of thevalve element, for instance of the bag, a layer of soft plastic matterof a certain thickness so as to facilitate the packing of the mouth ofthe orifice and to avoid that the resistant portion of the valve shouldundergo unnecessary deformations.

The hard and resistant portion of the valve element is represented at 8and the softer portion at 5.

However, it should be well understood that this construction of thevalve element constitutes only a preferred embodiment and that theinvention is in no way limited thereto.

What I claim is:

1. In a valve having a valve seat formed with a flat upper wall and afrusto-conical portion connecting said upper wall with a cylindricalduct, a valve element comprising a flexible plastic sheet adapted tocontact said upper wall and formed with a downwardly projectingfrusto-conical portion of plastic material softer than that of saidsheet and adapted to be wedged into said frustoconical portion of thevalve seat, the arrangement being such that the upper portion of saidsofter plastic portion is maintained under tension while the valve isclosed and the lower portion of said softer plastic portion ismaintained under compression.

2. In a valve having a valve seat formed with a flat upper wall and afrusto-conical portion connecting said upper wall with a cylindricalduct, a valve element comprising a flexible plastic sheet adapted tocontact said upper wall and formed with a downwardly projectingfrustoconical portion of plastic material softer than that of said sheetand adapted to be wedged into said frusto-conical portion of the valveseat in closing said valve, the said softer plastic portion reaching apoint of pressure equilibrium well above said cylindrical duct when thevalve is closed, with the portion of said frusto-conical plastic portionabove said point of equilibrium maintained in tension and the portionbelow said point of equilibrium under compression.

JEAN LOUIS GRATZM'ULLER-

